Roof joists
No matter what style of roof you are designing, it is likely that roof joists – whether in the form of horizontal ceiling joists or rafters at an angle - will be an important part of the design.
STEICO I-joists offer a versatile rafter solution suitable for most developments and provide a range of benefits and work in unison with roof beams to support the roof and transfer its weight down the walls and into the foundations.
How roof joists work as part of your overall roof system
Roof joists in the form of ceiling joists and rafters form a key part of your overall roof design.
Ceiling joists are laid horizontally across the roof, spaced evenly and parallel along the whole length of the structure. They are a common feature of both flat and pitched roofs and can either be exposed or concealed depending on the design.
Ceiling joists work to support other elements of the roof system, including:
- The roof beam
- Rafters
- As an integral part of a Truss forming the bottom cordCeiling joists also offer the structure for insulation of the roof space. Insulation boards or air-injected insulation can be installed between the ceiling joists to potentially improve the thermal and acoustic performance of the roof system.
Rafters are installed at an angle along the line of a pitched roof and are spaced evenly and parallel to form the primary framework of the roof.
Rafters work to support other elements of the roof system and transfer loads downwards to the load bearing walls and foundations including:
- Roofing materials (dead loads)
- Snow and wind loading (live loads)Rafters also offer the structure for insulation of the roof space that can be installed above, below or between the rafters, to potentially improve the thermal and acoustic performance of the roof system.
Ceiling joists are laid horizontally across the roof, spaced evenly and parallel along the whole length of the structure. They are a common feature of both flat and pitched roofs and can either be exposed or concealed depending on the design.
Ceiling joists work to support other elements of the roof system, including:
- The roof beam
- Rafters
- As an integral part of a Truss forming the bottom cordCeiling joists also offer the structure for insulation of the roof space. Insulation boards or air-injected insulation can be installed between the ceiling joists to potentially improve the thermal and acoustic performance of the roof system.
Rafters are installed at an angle along the line of a pitched roof and are spaced evenly and parallel to form the primary framework of the roof.
Rafters work to support other elements of the roof system and transfer loads downwards to the load bearing walls and foundations including:
- Roofing materials (dead loads)
- Snow and wind loading (live loads)Rafters also offer the structure for insulation of the roof space that can be installed above, below or between the rafters, to potentially improve the thermal and acoustic performance of the roof system.
What makes timber a good choice for roof joists?
Timber is one of the most common materials used for roof joists either in the form of ceiling joists or rafters. Timber offers a range of features that can benefit your project when specified and installed correctly, including:
- Ease of installation – Timber roof joists can be manipulated and modified with standard tools and are relatively easy to install compared to heavier steel joists which may need specialised equipment to move into place.
- Sustainability - Timber roof joists can be sourced responsibly from PEFC-certified forests (PEFC/04-31-2550) and can bind carbon from the atmosphere during Life Cycle Stage A1 as defined in EN 15804+A2 of your roof system, contributing towards your sustainability goals.
- Cost effective – Timber floor joists are a cost-effective option, are commonly available and quick to produce compared to steel alternatives.
The advantages offered to your project by STEICO I-joists
STEICO I-joists are an engineered timber solution that is suitable for use as roof joists on residential and commercial projects. They are made up of two parts:
- Flanges which are Laminated Veneer Lumber (LVL).
- The web section that joins the flanges which is made from Natural Fibre Boards.
This construction creates the ‘I’ shape of the beam and offers a range of benefits when specified and installed correctly, including:
- Up to 8% u-value improvement. Reduced thermal bridging due to the 8mm Natural Fibre Board web material. Can improve the u-value by up to 8% depending on the floor thickness
- Minimal shrinkage and twisting thanks to moisture content of just 9%.
- Sourced responsibly from PEFC accredited forests at the end of their life, so our I-joists are suitable for environmentally conscious build strategies.
